Induced Condensing Agent Composition for Higher Polyolefin Output
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Solution Overview
Problem
Existing polyolefin production processes face challenges in increasing production rates while avoiding reactor stickiness and agglomeration issues due to excessive concentrations of induced condensing agents (ICA), which can lead to cohesive or sticky polymer particles and solidification of the fluid bed.
Innovation Solution
Adjusting the composition of ICAs by increasing the concentration of lower molecular weight components and altering the ICA equivalency factor to increase the dew point approach temperature, thereby enhancing polyolefin production rates without causing stickiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the concentration of induced condensing agents (ICA) is increased to enhance polyolefin production rates, then productivity increases, but polymer particles become cohesive or sticky leading to agglomeration and reactor plugging
Solution Approach 1:
The patent changes the chemical composition parameters of the ICA by replacing higher molecular weight components (isopentane, n-pentane) with lower molecular weight components (n-butane, isobutane). This parameter change increases the dew point of the recycle stream, enhancing condensation efficiency and heat transfer while maintaining polymer particle stability and preventing stickiness, thus resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent utilizes phase transition of the ICA components by condensing the recycle stream below its dew point to form a two-phase gas/liquid mixture. The liquid phase provides enhanced heat transfer for vaporization in the fluidized bed, increasing production rate while the controlled phase transition prevents excessive polymer stickiness by regulating the condensation process
2Productivity
If the recycle stream temperature is lowered below the dew point to increase condensation and production rate, then productivity increases, but polymer particles become sticky and agglomeration occurs
Solution Approach 1:
The patent changes the thermal parameters by operating at higher dew point temperatures through ICA composition modification. This allows the recycle stream to be cooled below the dew point for enhanced condensation while the elevated dew point prevents excessive polymer stickiness, simultaneously achieving high productivity and preventing harmful effects
3Productivity
If excessive ICA concentrations are used to maximize heat transfer and production rate, then productivity increases, but the fluid bed solidifies forming large chunks that impair reactor operation
Solution Approach 1:
The patent changes the compositional parameters of the ICA to lower molecular weight components with higher dew points. This allows operation at higher ICA concentrations for maximum heat transfer and production rate while the elevated dew point maintains fluid bed stability by preventing solidification and chunk formation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for higher polyolefin production rates by maintaining stickiness temperatures, mitigating the drawbacks of excessive ICA concentrations, and preventing reactor issues.
Implementation Method 1
When a recycle stream temperature is lowered to a point below its dew point in condensed mode operation, an increase in polymer production may be possible. Cooling of the recycle stream to a temperature below the gas dew point temperature produces a two-phase gas/liquid mixture
Implementation Method 2
The liquid phase of this two-phase gas/liquid mixture in condensed mode operation is generally entrained in the gas phase of the mixture. Vaporization of the liquid occurs only when heat is added or pressure is reduced. Generally, the vaporization occurs when the two-phase mixture enters the fluidized bed, with the resin providing the required heat of vaporization
Implementation Method 3
since the polymerization reaction is exothermic, the amount of polymer produced in a fluidized bed polymerization process may be related to the amount of heat that can be withdrawn from the reaction zone
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Polyolefin polymerization performed by contacting in a reactor an olefin monomer and optionally a comonomer with a catalyst system in the presence of induced condensing agents (ICA) and optionally hydrogen. The ICA may include two or more ICA components where the composition of the ICA (i.e., the concentration of each ICA component) may affect the polyolefin production rate. Changes to the relative concentration of the two or more ICA components may be according to ICA equivalency factors that allow for increasing the polyolefin production rate while maintain a sticking temperature, increasing polyolefin production rate while increasing the dew point approach temperature of the ICA, or a combination thereof.